Stroke is a major medical problem in the UK. Each year, 110 000 people will suffer a stroke and between 20–30% of these will die within one month. 11% of all deaths in the UK are related to stroke and 25% of strokes will occur in patients under 65 years of age.
With such a major load on the medical system, it is not surprising that the Department of Health (DH) took an interest in the topic and in 2001 published a National Service Framework document, advising on topics that needed addressing by commissioners and suppliers (DH, 2001). This was followed in December 2007 by the National Sroke Strategy document describing best practice as it currently existed (DH, 2007).
As is often the case with such documents, the headline points seem to be incontrovertible, but again, as is commonly the case, there is devil in the detail where clinical and commissioning groups can have different views about what is meant within the wording—consequently, services develop differently in different areas depending upon who gets the upper hand in planning discussions.
The National Stroke Strategy
The strategy document (DH, 2007) sets out quality markers covering all aspects of the stroke service (Box 1). As professionals in the field, you may have seen changes deriving from this strategy. On the awareness front, it was apparent that few of the public knew what the signs of stroke were. Also, for many years there had been little other than rehabilitation available for stroke patients, so they were not considered as high priorities by either primary or secondary care or ambulance services.
In response, we have seen the FAST adverts, including those depicting patients with a flame in their head.
Patients suffering a TIA (or mini stroke) can now be risk stratified in emergency departments selecting those at greatest risk for admission and urgent investigation. Those at lower risk can be referred to rapid access clinics where investigations can be completed, reviewed and treatments initiated that have been shown to reduce (although not remove) the risk of stroke to that patient. There are time targets set for these clinics, designed to give the clinicians leverage to get funding for these services.
As is always the case, when new treatments become available, there will be early implementers who take an evangelical view of how the treatment should be applied, and of course there will be the turf wars over who should apply the treatment. Those who have served in the frontline services over the last 20 years will have seen an example of this in thrombolysis for ST elevation acute myocardial infarction.
When treatment first became possible, it could only be offered by cardiologists on the CCU. The assessment and selection of the patient was considered complex and dangerous. This limitation introduced delays in patient care.
The emergency departments became ‘able’ to apply this treatment and recently it has become standard for paramedics to offer cardiac thrombolysis in the field. Now patients are being offered PCI instead and the care package evolves again.
FAST
As a consequence of the stroke strategy, a version of FAST: Face, Arm, Speech, Test all Three, is being rolled out across the ambulance service. In North Yorkshire, because we now offer thrombolysis, we ask the ambulance crews for two further T's; Time of onset and Tell us, asking for a pre–alert.
Educational meetings aimed at emergency physicians and medical admitting teams allow ‘thrombolysis evangelists’ to explain the ‘apparently’ simple logistics involved in setting up a stroke thrombolysis service.
The recent developments in acute stroke care have evolved from early studies in the mid 1990's where thrombolysis was first attempted for stroke based on the success of cardiac thrombolysis in the 1980's. The early results were very mixed but with refinement, a group of patients were identified who derived benefit from treatment. This group is tightly time limited. Treatment only has a positive effect on recovery if given before four and a half hours. Until 2010, the time limit was three hours only but a recent international study (ECASS3) showed that a small number beyond three hours did gain.
As well as tight time limits, the patient must have an essentially normal CT scan before treatment.
Cause and assessment
Stroke is caused by failure of the blood supply to sections of the brain, resulting in death of brain tissue. 80% of these supply failures are due to occlusion of the blood vessel by either clots forming on areas of atherosclerosis within the blood vessels, or emboli of clot material from the heart in patients with atrial fibrillation or the carotid arteries in patients with atherosclerosis of that area.
Twenty percent of stroke is due to a bleed from an atherosclerotic vessel in the brain. When the brain tissue dies due to occlusion, the blood vessels downstream of the blockage also die—since they are living structures, themselves dependent on a blood supply. These pathological facts define the logic of the time limit for treatment by thrombolysis.
When assessing a patient, the clinician who has to make the decision needs to know when the stroke started, not when it was first noticed. Consequently we need the time of onset. ‘It happened as I was making breakfast at 08.30’ is good, whereas ‘I noticed I could not stand when I woke and tried to go to the toilet’ is bad because the stroke occurred while they were asleep and consequently we do not know when.
Treatment
The patient must have a new neurological deficit that is consistent with damage to an area of the brain. There are some neurological symptoms that can be mistaken for stroke unless care is taken with the history and the examination. Subjecting a patient to a potentially dangerous drug requires a proper balance of the risks.
A rapid access to CT must be available. The studies so far, show that the earlier the treatment, the better the results. Although there is a four and a half hour treatment window, the results after three hours are very much worse than before three hours (although better than no treatment) and there are far fewer patients who will have an appropriate CT for treatment after three hours.
‘Close working between the ambulance service and the receiving hospital can ensure that a meaningful number of patients can be offered a therapy that provides a real improvement’
The CT is performed to rule out contraindications to thrombolysis, not to show the presence of a stroke. In the early stages of a stroke, there are very few visible signs on a CT.
It is obvious that treating a haemorrhage with a thrombolytic would not be beneficial so CT signs of haemorrhage are sought.
If the CT reveals oedema in the distribution of a cerebral blood vessel, then this is a sign of brain cell death. Giving a thrombolytic to such patients is likely to reopen the blood vessels just as their structural strength fails increasing the risk of haemorrhage.
Other causes of weakness such as tumour will show on CT and of course are not going to respond to this treatment.
Having ascertained that the patient has a new onset stroke, is within the time frame and has a CT that does not prevent treatment, and does not have any other contraindications like recent surgery that would place the patient at risk from the treatment, then they are given an intravenous dose of the thrombolytic agent over one hour.
They then require observing over the next 12 hours (in my service, on the CCU) watching for the normal complications of thrombolysis such as bleeding, as well as recording any neurological changes, until the patient is transferred to the stroke unit for secondary prevention and rehabilitation.
At 48 hours, the patient undergoes a second CT scan to record how much damage has occurred, since it is rare to see no changes even if the clinical signs have resolved.
This sequence of care requires local services to be co-ordinated and here is where vested interests can cause problems with delivery.
Marker of quality
The Stroke Strategy contains the following ‘marker of quality’: Quality Marker 7. Urgent response:
All patients with suspected acute stroke are immediately transferred by ambulance to a receiving hospital providing hyper-acute stroke services (where a stroke triage system, expert clinical assessment, timely imaging and the ability to deliver intravenous thrombolysis are available throughout the 24-hour period).
In many regions, this statement has been interpreted as requiring the patient to be taken to a ‘hyperacute’ stroke unit staffed with several stroke specialists. This requires a complex triage of patients in the field with decisions made to transfer, not to the nearest hospital but to the regional centre.
Whereas this might be easy in a conurbation with hospitals close together, it does add complexity to the crews' decision-making and becomes seriously problematical when extended transfer times are needed with vehicles having to go out of region to comply.
Rural services with widely scattered hospitals would have great difficulty in complying within the timescales and therefore a postcode lottery is built into centralized services by the very nature of the transport problem.
Some teams feel that the assessment and treatment of these patients is not intrinsically difficult for the emergency department and so this treatment is well within the abilities of a normal ED much as cardiac thrombolysis is.
With prealerts from our ambulance crews who routinely perform FAST assessment including an onset time, we are able to prioritize the incoming patient to a senior ED clinician who can order an urgent CT.
Currently, the national stroke thrombolysis rate is approximately 0.5% of strokes, whereas the strategy document suggests a 10% target. In Scarborough, an isolated district general hospital, 90 minutes from the nearest tertiary centre, but with support from the ambulance service, radiology and the hospital's coronary care and stroke units, we gave thrombolysis to 14% of the patients attending with symptoms of stroke in 2009/10 using our integrated pathway.
Acute stroke care, such as the management of cardiac resuscitation and trauma, is an area where close working between the ambulance service and the receiving hospital can ensure that a meaningful number of patients can be offered a therapy that gives real improvement to a previously under treated patient group.
The paramedic role may be a simple FAST and time assessment with pre-alert or may require complex decision-making as to transit time and distance from the regional acute centre. In either case, the paramedic services will have to be involved in the planning of the service for it to have any chance of working.